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| author | Conor Dooley <conor.dooley@microchip.com> | 2025-01-22 14:42:56 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-17 11:36:42 +0100 |
| commit | c3ac0c29f48d2d934e215aecab3b11779c2f1112 (patch) | |
| tree | 35edb77eb140cff7a2015bf7f1a11044f6fe7f63 | |
| parent | 15b5bb9012175ac9ed1d8481338d12cd9a6af43d (diff) | |
| download | linux-c3ac0c29f48d2d934e215aecab3b11779c2f1112.tar.gz linux-c3ac0c29f48d2d934e215aecab3b11779c2f1112.tar.bz2 linux-c3ac0c29f48d2d934e215aecab3b11779c2f1112.zip | |
pwm: microchip-core: fix incorrect comparison with max period
commit 752b6e3af374460a2de18f0c10bfa06bf844dbe8 upstream.
In mchp_core_pwm_apply_locked(), if hw_period_steps is equal to its max,
an error is reported and .apply fails. The max value is actually a
permitted value however, and so this check can fail where multiple
channels are enabled.
For example, the first channel to be configured requests a period that
sets hw_period_steps to the maximum value, and when a second channel
is enabled the driver reads hw_period_steps back from the hardware and
finds it to be the maximum possible value, triggering the warning on a
permitted value. The value to be avoided is 255 (PERIOD_STEPS_MAX + 1),
as that will produce undesired behaviour, so test for greater than,
rather than equal to.
Fixes: 2bf7ecf7b4ff ("pwm: add microchip soft ip corePWM driver")
Cc: stable@vger.kernel.org
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250122-pastor-fancied-0b993da2d2d2@spud
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/pwm/pwm-microchip-core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-microchip-core.c b/drivers/pwm/pwm-microchip-core.c index c1f2287b8e97..12821b4bbf97 100644 --- a/drivers/pwm/pwm-microchip-core.c +++ b/drivers/pwm/pwm-microchip-core.c @@ -327,7 +327,7 @@ static int mchp_core_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device * * mchp_core_pwm_calc_period(). * The period is locked and we cannot change this, so we abort. */ - if (hw_period_steps == MCHPCOREPWM_PERIOD_STEPS_MAX) + if (hw_period_steps > MCHPCOREPWM_PERIOD_STEPS_MAX) return -EINVAL; prescale = hw_prescale; |